172 MEMORANDA. 



terhwi. They are alluded to by Mr. Osborne, and are depicted 

 in several of Ralf's figures, particularly in C. Ralfsii, and 

 were even more definitely displayed in several fronds of 

 C didymotocum, sent to me among some mud from near Beau- 

 maris, of one of which I took an outline with the camera in 

 my note-book, in July 1853, resembling the sketch enclosed. 



This frond seemed nearly, or quite dead ; it was partly trans- 

 parent, the endochrome contracted, and some portion had 

 escaped. Several apertures penetrated both layers of the 

 investing membrane at irregular intervals, the inner circle of 

 the aperture being the more distant from the eye in all save 

 one (marked x ), in which the larger orifice seemed in the 

 opposite direction. All around the apertures and over the 

 entire space not occupied by endochrome, were crowded 

 myriads of excessively minute atoms in active motion. Are 

 these perforations accidental or belonging to the economy of 

 the Closterium ; and have they any affinity with the mysterious 

 hyaline globule at its extremity ? I have noticed groups of 

 busy granules in apparently hyaline vesicles on the dark 

 surface of the frond, though I could not identify them with 

 the spots here designated as apertures. 



l^he application of iodine was merely a repetition of Mr. 

 Dalrymple and others' experiments, and, like his early attempts, 

 failed to denote the presence of starch in the endochrome. 

 And yet the Closterium seemed a fully mature specimen. 



I have not had leisure to watch the process of division 

 observed by Mr. Osborne, but have noticed the motion of the 

 Closterium from side to side, recorded by him, a movement 

 which appeared to me perfectly spontaneous ; and, indeed, 

 without some means of spontaneous motion it is difficult to 

 conceive how the frond (I had almost said the aiiimalcule') 

 becomes removed from the bottom to the sides of a glass, a 

 fact I have especially noticed in some of the kindred species, 

 Docidium. 



The above observations were made chiefly by the light of a 

 camphine lamp, or of a sperm candle intensified by a Ross* 

 condenser, and with one of Ross' l-8th of an inch objectives, 

 of 150° angle of aperture. I have not yet used the direct 

 sunlight recommended by recent observers, but shall certainly 

 adopt it when the return of spring gives further opportunities 

 lor the re-investigation of these very beautiful and interesting 

 objects.— F. G. Wright, M. D., Wakejield. 



